Re: non-exclusive backup cleanup is mildly broken

On Fri, Dec 13, 2019 at 9:00 AM Michael Paquier <michael(at)paquier(dot)xyz> wrote:

> On Thu, Dec 12, 2019 at 01:52:31PM +0100, Magnus Hagander wrote:
> > On Thu, Dec 12, 2019 at 5:58 AM Kyotaro Horiguchi <
> horikyota(dot)ntt(at)gmail(dot)com>
> > wrote:
>
> > My first reaction would be to just disallow the combination of prepared
> > transactions and start/stop backups. But looking at it it seems like an
> > unnecessary restriction and an approach like this one seems better.
>
> I think that's a bad idea to put a restriction of this kind. There
> are large consumers of 2PC, and everybody needs backups.
>

You misunderstood me. I certainly didn't mean that people who use 2PC
shouldn't be able to use proper backups -- that would be *terrible*.

I meant disallowing pg_start_backup() in a session that had a prepared
transaction, and disallowing preparing a transaction in a session with an
ongoing backup. They would still work perfectly fine in *other* parallel
sessions.

That said, being able to do it in the session itself is of course even
better.

--
Magnus Hagander
Me: https://www.hagander.net/ <http://www.hagander.net/>
Work: https://www.redpill-linpro.com/ <http://www.redpill-linpro.com/>